In general, various forms of displays have been commercialized recently, and electromagnetic interference (EMI) due to electromagnetic noise occurred in the display causes problems such as harm to human bodies and malfunction of machinery. To solve these problems, there is a method which includes forming a conductive shielding film in front of display, distorting the progressing direction of the electromagnetic waves, and releasing through earthing.
As a method of shielding electromagnetic wave noise occurred in front of display such as CRT, PDP, etc., a method of forming a thin conductive film by vapor-depositing metal or metal oxide on a transparent substrate is known. However, the film must be deposited thinly to provide a transparency, and in this case, surface resistance of conductive layer becomes too high to get a sufficient electromagnetic shielding effect.
The most generally used method is metal foil etching, which includes adhering a thin copper film on a transparent substrate, forming a photoresistor pattern by exposure, and forming a copper pattern by etching the thin copper film using the photoresistor pattern. However, this method has a long and complicated procedure, makes much metal wastes and thus is not good for environment. Further, the method causes a problem, in that nodes of copper pattern bulge during procedures.
In addition to the above mentioned methods, there has been reported a method which includes forming a pattern by printing conductive paste, for example, by screen printing and offset printing, and forming electromagnetic waves-shielding film by electroless plating. This method has a precision limit on printed-circuit board. In addition, the method has a problem that conductive materials sink into uneven parts.
As a photo development method, a method including forming a metal layer, and plating or electroless plating it is disclosed, but this developing method has drawbacks in that several layers and complicated procedures are necessary. Meanwhile, there is reported a method which includes mixing a metal catalyst with photosensitive resin, followed by development, and then electroless plating or electro plating. However, this method uses a precious Pd as a catalyst and it doesn't disclose a solution about the problem like pattern detach in strong alkaline aqueous solution, accompanied by electroless plating. In the case of electroless plating, deposition efficiency might be improved, but a solution about pattern detach in strong alkaline aqueous solution was not disclosed.